Ubi has released a patch for the retail version of Far Cry. Changes include tweaks to most of the weapons, quicksave added to singleplayer, run speed increased, sprint lasts longer, a bunch of Punkbuster fixes, and lots more.
The official Far Cry site has links to the 65MB patch, and so does 3DGamers:
***UPDATE*** Ubi has now withdrawn the 1.2 patch due to "unexpected behaviour on specific hardware configurations." FileFront is still hosting the patch here.